Buggy code:
private TaskData result ) { } @ Override public void onCancelled ( ) { } } ; private TaskListener mUpdateCardHandler = new DeckTask . TaskListener ( ) { private boolean mNoMoreCards ; @ Override public void onPreExecute ( ) { } @ Override public void onProgressUpdate ( DeckTask ... values ) { } @ Override public void onPostExecute ( DeckTask . TaskData result ) { } @ Override public void onCancelled ( ) { } } ; protected TaskListener mAnswerCardHandler = new DeckTask . TaskListener ( ) { private boolean mNoMoreCards ; @ Override public void onPreExecute ( ) { } @ Override public void onProgressUpdate ( DeckTask ... values ) { } @ Override public void onPostExecute ( DeckTask . TaskData result ) { } @ Override public void onCancelled ( ) { } } ; private void updateTypeAnswerInfo ( ) { } private String typeAnsQuestionFilter ( String buf ) { } private String typeAnsAnswerFilter ( String buf , String userAnswer , String correctAnswer ) { } private String contentForCloze ( String txt , int idx ) { } private Handler mTimerHandler = new Handler ( ) ; private Runnable removeChosenAnswerText = new Runnable ( ) { @ Override public void run ( ) { } } ; protected int mWaitAnswerSecond ; protected int mWaitQuestionSecond ; protected int getDefaultEase ( ) { } @ Override protected void onCreate ( Bundle savedInstanceState ) { } @ Override public void onConfigurationChanged ( Configuration config ) { } protected abstract void setTitle ( ) { } @ Override protected void onCollectionLoaded ( Collection col ) { } @ Override protected void deselectAllNavigationItems ( ) { } @ Override protected void onPause ( ) { } @ Override protected void onResume ( ) { } @ Override protected void onDestroy ( ) { } @ Override public void onBackPressed ( ) { } @ Override public boolean onKeyDown ( int keyCode , KeyEvent event ) { } @ Override public boolean onKeyUp ( int keyCode , KeyEvent event ) { } protected boolean clipboardHasText ( ) { } private void clipboardSetText ( CharSequence text ) { } private CharSequence clipboardGetText ( ) { } @ Override protected void onActivityResult ( int requestCode , int resultCode , Intent data ) { } protected long getParentDid ( ) { } public GestureDetector getGestureDetector ( ) { } private void registerExternalStorageListener ( ) { } private void stopTimer ( ) { } private void restartTimer ( ) { } protected void undo ( ) { } private void finishNoStorageAvailable ( ) { } protected boolean editCard ( ) { } protected void generateQuestionSoundList ( ) { } protected void lookUpOrSelectText ( ) { } private boolean lookUp ( ) { } private void showLookupButtonIfNeeded ( ) { } private void hideLookupButton ( ) { } protected void showDeleteNoteDialog ( ) { } private int getRecommendedEase ( boolean easy ) { } protected void answerCard ( int ease ) { } protected void initLayout ( ) { } @ SuppressLint ( "NewApi" ) private WebView createWebView ( ) { } private void invertColors ( boolean invert ) { } protected void showEaseButtons ( ) { } protected void hideEaseButtons ( ) { } private void switchTopBarVisibility ( int visible ) { } protected void initControls ( ) { } protected SharedPreferences restorePreferences ( ) { } private void setInterface ( ) { } private void setDueMessage ( ) { } private void updateForNewCard ( ) { } protected void updateScreenCounts ( ) { } protected Handler mTimeoutHandler = new Handler ( ) ; protected Runnable mShowQuestionTask = new Runnable ( ) { @ Override public void run ( ) { } } ; protected Runnable mShowAnswerTask = new Runnable ( ) { @ Override public void run ( ) { } } ; protected void initTimer ( ) { } protected void displayCardQuestion ( ) { } protected String cleanCorrectAnswer ( String answer ) { } protected String cleanTypedAnswer ( String answer ) { } protected void displayCardAnswer ( ) { } public String getAnswerFormat ( ) { } private void updateCard ( String content ) { } private String SmpToHtmlEntity ( String text ) { } protected void playSounds ( boolean doAudioReplay ) { } private static void readCardText ( final Card card , final int cardSide ) { } private JSONObject getConfigForCurrentCard ( ) { } private static long getDeckIdForCard ( final Card card ) { } public void fillFlashcard ( ) { } public void showFlashcard ( boolean visible ) { } public static Card getEditorCard ( ) { } private static String enrichWithQADiv ( String content , boolean isAnswer ) { } private String recalculateHardCodedFontSize ( String content , int percentage ) { } private final boolean typeAnswer ( ) { } private static int calculateDynamicFontSize ( String htmlContent ) { } private void unblockControls ( ) { } private void blockControls ( ) { } private void selectAndCopyText ( ) { } private boolean shouldUseQuickUpdate ( ) { } protected void executeCommand ( int which ) { } public final class AnkiDroidWebChromeClient extends WebChromeClient { @ Override public boolean onJsAlert ( WebView view , String url , String message , JsResult result ) { } } protected void closeReviewer ( int result , boolean saveDeck ) { } protected void refreshActionBar ( ) { } class MyWebView extends WebView { public MyWebView ( Context context ) { } @ Override public boolean onCheckIsTextEditor ( ) { } @ Override protected void onScrollChanged ( int horiz , int vert , int oldHoriz , int oldVert ) { } private final Handler scrollHandler = new Handler ( ) ; private final Runnable scrollXRunnable = new Runnable ( ) { @ Override public void run ( ) { } } ; private final Runnable scrollYRunnable = new Runnable ( ) { @ Override public void run ( ) { } } ; } class MyGestureDetector extends SimpleOnGestureListener { @ Override public boolean onFling ( MotionEvent e1 , MotionEvent e2 , float velocityX , float velocityY ) { } @ Override public boolean onDoubleTap ( MotionEvent e ) { } @ Override public boolean onSingleTapUp ( MotionEvent e ) { } @ Override public boolean onSingleTapConfirmed ( MotionEvent e ) { } } @ Override public boolean onTouchEvent ( MotionEvent event ) { } class ScrollTextView extends TextView { public ScrollTextView ( Context context ) { } @ Override protected void onScrollChanged ( int horiz , int vert , int oldHoriz , int oldVert ) { } private final Handler scrollHandler = new Handler ( ) ; private final Runnable scrollXRunnable = new Runnable ( ) { @ Override public void run ( ) { } } ; private final Runnable scrollYRunnable = new Runnable ( ) { @ Override public void run ( ) { } } ; } private TagHandler mSimpleInterfaceTagHandler = new TagHandler ( ) { @ Override public void handleTag ( boolean opening , String tag , Editable output , XMLReader xmlReader ) { } private Object getLast ( Editable text , Class kind ) { } } ; private ImageGetter mSimpleInterfaceImagegetter = new Html . ImageGetter ( ) { @ Override public Drawable getDrawable ( String source ) { } } ; private Spanned convertToSimple ( String text ) { } private String removeFrontSideAudio ( String answerContent ) { String answerFormat = getAnswerFormat ( ) ; if ( answerFormat . contains ( "{{FrontSide}}" ) ) { String frontSideFormat = mCurrentCard . _getQA ( false ) . get ( "q" ) ; Matcher audioReferences = sSoundPattern . matcher ( frontSideFormat ) ; while ( audioReferences . find ( ) ) { <START_BUG> answerContent = answerContent . replaceFirst ( audioReferences . group ( ) , "" ) ; <END_BUG>

Fix:
answerContent = answerContent . replaceFirst ( Pattern . quote ( audioReferences . group ( ) ) , "" ) ;